1. Field of the Invention
The present invention relates to a device for separating oil from blow-by gases, and more particularly, to a device for separating oil, which is integrally provided to a head cover of an engine so as to make the engine be compact and also to improve oil separating efficiency.
2. Description of Related Art
Emissions from automobiles are generally divided into three types according to their sources: exhaust gas produced through the combustion of fuel-air mixture in a cylinder and exhausted via an exhaust system; evaporation gas evaporated from fuel in a fuel tank; and blow-by gas, such as a portion of the fuel-gas mixture or unburned gas, which has leaked into a crank case from a combustion chamber.
Here, the blow-by gas indicates gas, which has leaked into the crank case from the combustion chamber through a gap between a cylinder and a piston during a compression stroke and an expansion stroke. The blow-by gas, after having leaked into the crank case from the combustion chamber, passes sequentially through a blow-by gas passage, a cylinder head and a head cover of a cylinder block.
The blow-by gas creates some problems, which are more severe in a diesel engine than in a gasoline engine. This is because, in case of the diesel engine having a high compression ratio, compressed gas under high pressure leaks into the crank case from the cylinder through the gap between the cylinder and the piston. Especially, in a diesel engine using a turbocharger, when a blow-by gas outlet of the crank case or the cylinder head is directly connected to a suction passage, high negative suction pressure increases flow rate thereby lowering pressure, so that the blow-by gas is rapidly absorbed from the crank case into the suction side, thereby dropping the pressure inside the crank case to be abnormally low. This as a result can cause critical damages to the quality and endurance of the engine. For example, the consumption of engine oil sharply increases, oil leaks from respective seals, or dust is introduced into the engine.
Considering that the blow-by gas gives an adverse effect to the quality of the exhaust gas and the engine may consume more engine oil when more blow-by gas is produced, it is more important among others to completely separate engine oil, which moves along with a flow of the blow-by gas, from the blow-by gas while effectively circulating the blow-by gas. For this, the flow of the blow-by gas is obstructed so that the oil can be separated from the blow-by gas through collision. Further, a filter or the like is installed on a flow path of the blow-by gas in order to separate cohesive oil droplets from the blow-by gas when the blow-by gas is passing through the filter.
In order to separate the oil from the blow-by gas, an external separator is additionally mounted on the exterior of the head cover or a baffle or a sheet of nonwoven cloth is mounted inside the head cover.
However, the method of separating engine oil using the baffle or the nonwoven cloth does not sufficiently separate the oil and thus is not suitable to be used in consideration of latest emission regulations, which are getting gradually stronger. Furthermore, the external separator mounted on the head cover increases the size of the engine, thereby making it difficult to design the engine to be compact.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.